Evans won the bet but still donned his Marvel costume for charity.

On Saturday, Evans — a New England Patriots fan — made good on his promise to don his Captain America duds for a visit to Seattle Children's Hospital with Guardians of the Galaxy star Pratt. The visit stems from their bet that the person whose favorite team lost in the big NFL game would appear in character at a charity of the other's choosing.

One photo posted to Twitter from Saturday's visit shows Evans holding up his shield next to a young boy in a hospital bed. The boy is wearing a Captain America shirt.

"Meeting Captain America and Star-Lord is an experience our patients will always remember. #TwitterBowl," reads a message from the hospital's Twitter feed. According to the hospital's rep, the stars requested that the media not find out about the visit ahead of time, so that the focus could remain on the patients.

Maggie Mittelstaedt, an 18-year-old recovering from a hip replacement, said that seeing the actors lifted her spirits. "It really brightened my day!" she said. "I am a huge fan and they were so nice to spend time with me."

Tyler Gower, a 14-year-old diagnosed with acute myeloid leukemia, is Pratt's biggest fan. "It gave Tyler five minutes of happiness," his mom, Allison, said of the visit. "This situation will never be normal, but their visit helped make us feel special."

Pratt took to Facebook, where he shared The Hollywood Reporter's story about the visit. "Had the immense joy yesterday of joining the real Captain America at Seattle Children's Hospital," Pratt wrote. "Thanks to Chris Evans for being a classy ‪#‎twitterbowl‬ winner."

Pratt was in street clothes Saturday but dressed as Star-Lord to visit Boston's Christopher's Haven cancer charity on Feb. 6, after Pratt's beloved Seattle Seahawks lost to the Patriots. Evans, who can be seen in May's The Avengers: Age of Ultron, had tweeted shortly after the game that he would return the favor for Pratt's charity, even though his team won.

Photos, courtesy of Seattle Children's Hospital, can be seen below. Tweets and Pratt's Facebook post are also below.